Move condition in CollapsedBorderValue::Width() into constructor

third_party/WebKit/Source/core/layout/CollapsedBorderValue.h

Index: third_party/WebKit/Source/core/layout/CollapsedBorderValue.h
diff --git a/third_party/WebKit/Source/core/layout/CollapsedBorderValue.h b/third_party/WebKit/Source/core/layout/CollapsedBorderValue.h
index d555c97fd2f81c6c81e1ea07a76c5e68eb75edc0..8c5c5b628a96897259230d09fdb3bdae399be2af 100644
--- a/third_party/WebKit/Source/core/layout/CollapsedBorderValue.h
+++ b/third_party/WebKit/Source/core/layout/CollapsedBorderValue.h
@@ -56,14 +56,14 @@ class CollapsedBorderValue {
                        const Color& color,
                        EBorderPrecedence precedence)
       : color_(color),
-        width_(border.NonZero() ? border.Width() : 0),
+        width_(border.Style() > kBorderStyleHidden ? border.Width() : 0),

[Xianzhu, 2017/05/04 20:45:26]

BorderValue::NonZero() is:
 { return Width() && (style_ != kBorderStyleNone); }

width_ was and will be set to:
                               old code         new code
border.Width()==0                 0                0
Style()==kBorderStyleNone         0                0
Style()==kBorderStyleHidden    border.Width()      0

For both old code and new code, CollapsedBorderValue::Width() returns 0 in the
above cases, or otherwise the original border width.

[wkorman, 2017/05/04 21:13:04]

Seems like unit tests for these permutations could be helpful for future. It is
mainly a simple container class but there is some logic here and the class is
referenced by both LayoutTableCell and TableSectionPainter.

[Xianzhu, 2017/05/04 22:23:35]

Added tests.

         style_(border.Style()),
         precedence_(precedence),
         transparent_(border.IsTransparent()) {
     DCHECK(precedence != kBorderPrecedenceOff);
   }
 
-  unsigned Width() const { return style_ > kBorderStyleHidden ? width_ : 0; }
+  unsigned Width() const { return width_; }
   EBorderStyle Style() const { return static_cast<EBorderStyle>(style_); }
   bool Exists() const { return precedence_ != kBorderPrecedenceOff; }
   Color GetColor() const { return color_; }